Multigap spark-plug.



' M. M. METZIINGER.

MULTIGAP SPARK PLUG.

APPLICATION FILED APR. I8. 1918.

1 ,298,368. Patented Mar. 25, 1919.

MYRON M. METZINGER, 0F BLAIR, NEBRASKA.

MULTIGAP SPARK-PLUG.

Specification of Letters Patent.

Patented Mar. 25, 1919.

Application filed April 18, 1918. Serial No. 229,291.

7 '0 all whom it may concern:

Be it known that I, MYRON M. Mn'rznx'onn, a citizen of theUnitedstatesof America, residing at Blair, in the county of Washingtonand State of Nebraska, have invented certain new and useful Improvementsin Multigap Spark-Plugs, of which the following is a specification.

My invention relates to electric ignitiorl spark plugs for internalcombustion engines and the objects of my improvement are, first, toprovide means to prevent the fouling of the electrodes by thelubricating oil in the cylinders; second, to provide in a spark plug amultiplicity of spark gaps and thereby increase the probability of aspark and the certainty of the ignition of the fuel; third, to providean electrode that automatically works itself clean fromany foulingmatter, especially soot or carbon; fourth, the provision of means toprevent any misplacement of either electrode with reference to theother, during assembling, or displacement in transportation or duringregular use, whereby the spark gaps would be varied and the efliciencvof the plug injured or destroyed; and, fifth, to reduce the liability ofthe metal, at opposite sides of the gap, to become deteriorated bycharring. All of which objects, with others more particularlyhereinafter disclosed, I attain by the contrivance and structureillustrated by the accompanying drawing in whichigure 1, is a verticallongitudinal section, partly in side elevation; and Fig. 2, is an underend view. In all of which views similar reference numerals indicate likeparts of the structure.

The cylindrical exteriorly-threaded seating shell 2 receives thethreaded nut-headed gland 8 in its top end to securely seat theinsulation tube 9 therein; suitable gaskets 10 and 11 being provided,and all constructed and assembled in the usual manner and as shown inFig. 1. A vertical rod 12 disposed axially in the insulation tube issuitably connected to the binding post 13 and carries at 4 its lower endthe upper electrode 5.

The u per electrode is discal in shapeand dispose coaxial with itscurrent-connect ng and supporting rod .12 and has its lower facedisposed in aplane at right angles to its axis. The lower gap-face of111118 compound electrode consists of the pendent annular flange 6 alongits circumferentlal outer edge and the inner pendent annular flange 7 ofless diameter, spaced from the outer flange. The lower or projectingedges of these flanges are disposed in the same plane, at right anglesto their axis.

The opposite or lower electrode 3, consists of two U-shaped loops, theirbases arranged transversely and integrally connected at the centers oftheir bases,as shown in Fig. The connected bases form the four radialbars 4, 4, etc., their intersection agreeing with the axis of the discalelectrode above and all lying in a plane parallel with the pendent edgesof its flanges. The upstanding ends of the branches, at the outer endsof the radial bars, are seated and fastened in the lower rim of theseating shell 2, to set the radial bars spaced below the discalelectrode. Each radial bar is thus disposed crosswise of the edges ofboth annular flanges, and ?aced therefrom, forms two spark gaps.

he aggregate for the whole being eight spark gaps. For light service asingle radial arm supported at one side of the run of the seating shelland extending inwardly only to the axial line of the discal electrodeand giving two gaps, will suflice. But, for ordinary service at leastone full U-shaped loop, attached in opposite sides of the seating shellrim, as shown in Fig. 1, giving four spark gaps and a more stablestructure, is preferable.

It is obvious that a greater number of radial arms may be added, eachincreasing the number of spark gaps by two. When a magneto system is thesource of the electric current, the spark intensity normally varies withthe armature speed. This multiplicity of spark gaps, so arranged as tobe substantially equal in length,in resistance throughout the numericalfield of gaps, prevents the liability to that intense heating of theelectrodes which results in charring them.

Any accumulation of lubricating 011, even to the extent of flooding thesurfaces in the combustion chamber, will, invariably drip from the outerflange, leavin clean all gaps between the inner or smal er flange andthe radial bars beneath. It is obvious that accumulations of oil orother liquid obstructions will not stand on the top edges of the opposedradial bars. Further, the initial explosion, of the carbureted mixture,is of that portion occupying the central cavity and the groove lyingbetween the annular flanges of the face of the upper electrode; theforce of this initial explosion acting downwardly, toward and againstthe bars, cleans and retains them clean at and during each explosiveimpulse of the engine.

I claim:

1. In a device as described, in combination, a tubular shell, a plugheld against longitudinal displacement v and concentrically Within saidshell, in an elongated rod removably held againstlongitudinaldisplacement Within said plug and projecting eyond thelatter, and an integral disk electrode formed terminally upon theprojecting end of said rod, said disk being bored out to provide a pairof concentric rings upon its flat surface.

2. In a device as described, in combination, a shell, a plug mountedconcentrically therein, a rod removably carried by said plugconcentrically thereof, an enlarged portion formed terminally upon saidrod and projecting in spaced relation from said plug, said enlargedportion having an under flat side, said head being cored out so as toprovide a central ring, and a member having depending portions securedto said shell larged portion.

and including a portion extending transversely of said shell in parallelrelation oppositely to the under fiat side of said en-.

'3. In a device as described, in combination, a shell a plug securedconcentrically in said shell, a rod removably carried by said plugconcentrically thereof, and pro jecting therebeyond, an enlarged diskformed terminally upon the projecting portion of said disk being coredout centrally to provide an inner ring and being-formed with a,concentric annular. groove around said ring so as to provide an outerring and a member having four arms supported dependingly, from saidshell in a concentric relation and carrying tWo transverse arms arrangedat right angles to each other and parallel to the under side of saiddisk so as to form a central base portion directly under but larger thanthe bore of the inner ring of said disk.

In testimony whereof I have hereto affixed my signature.

MYRON M. METZINGER.

